Prevalence of CFTR mutations in hypertrypsinaemia detected through neonatal screening for cystic fibrosis.

Nowadays, most of the neonatal screening programs for cystic fibrosis (CF) combine the assay of immunoreactive trypsinogen (IRT) with the analysis of the most common mutations of the CFTR gene. The efficiency of this strategy is now well established, but the identification of heterozygotes among neonates with increased IRT is perceived as a drawback. We proposed to assess the heterozygosity frequency among the children with hypertrypsinaemia detected through the CF screening program implemented in Brittany (France) 10 years ago, to describe the CFTR mutations detected in them and to determine the frequency of the IVS8-5T variant. The molecular analysis relies, in our protocol, on the systematic analysis of three exons of the gene (7-10-11). A total of 160,019 babies were screened for CF in western Brittany between 1992 and 1998. Of the 1964 newborns with increased IRT (1.2%), 60 were CF and 213 were carriers. Heterozygosity frequency was 12.8%), i.e. 3 times greater than in the general population (3.9%; p < 10(-6)), Variability of mutations detected in carriers was greater than in CF children (21 mutations versus 10) and a high proportion of mild mutations or variants (A349V, R297Q, R347H, V317A, G544S, R553G, etc) was observed in carriers. The allelic frequency of the 5T (5.6%) was not significantly increased in this cohort. This study is consistent with previous ones in finding a significantly higher rate of heterozygotes than expected among neonates with hypertrypsinaemia. The strategy of screening used here allows to highlight the variability of mutations detected in heterozygotes and to show that severe mutations, as well as mild mutations, have been observed in neonates with hypertrypsinaemia. If there is no doubt that neonatal hypertrypsinaemia is associated with an elevated frequency of carriers, the underlying mechanisms remain obscure.

Neonatal screening for cystic fibrosis in Brittany, France: assessment of 10 years' experience and impact on prenatal diagnosis.

BACKGROUND: Neonatal screening for cystic fibrosis has been a subject of debate over the past few years. This study assesses 10 years of neonatal screening in Brittany, France, and examines its impact on prenatal screening of subsequent pregnancies in couples with an affected child. METHODS: The study included all the neonates screened for cystic fibrosis in Brittany from Jan 1, 1989, to Dec 31, 1998. The screening consisted of an immunoreactive trypsinogen assay from dried blood spots, plus, from 1993, mutation analysis. Data were collected on incidence of cystic fibrosis, and genotypic and biochemical characteristics. The use of prenatal screening of subsequent pregnancies in affected families was also investigated. FINDINGS: Of the 343,756 neonates screened, 118 children with cystic fibrosis were identified, giving an incidence of one in 2913. All mutated alleles were characterised: 34 different mutations resulting in 36 genotypes were detected. The introduction of DNA analysis into the protocol greatly reduced the recall rate and increased the sensitivity of the test. The mean cost of the screening programme was US$2.32 per screened child. 39 (34%) of the families identified by neonatal screening opted for subsequent prenatal diagnosis at least once. 12 couples would have benefited from this procedure while their first child was still symptom-free. 42 healthy children were born, and 18 pregnancies were terminated (therapeutic abortion rate of 100%). INTERPRETATION: We have shown the feasibility of neonatal screening for cystic fibrosis in Brittany. Through the detection of a large range of mutations, neonatal screening provides the opportunity for more reliable prenatal diagnosis and cascade screening. The neonatal screening programme described here could provide a good model for other countries intending to initiate such a scheme.

Blood concentrations of pancreatitis associated protein in neonates: relevance to neonatal screening for cystic fibrosis.

AIM: To determine whether pancreatitis associated protein (PAP) is a marker for cystic fibrosis which could be used in neonatal screening for the disease. METHODS: PAP was assayed on screening cards from 202,807 neonates. Babies with PAP > or = 15 ng/ml, or > or = 11.5 ng/ml and immunoreactive trypsinogen (IRT) > or = 700 ng/ml were recalled for clinical examination, sweat testing, and cystic fibrosis transmembrane regulator (CFTR) gene analysis. RESULTS: Median PAP value was 2.8 ng/ml. Forty four cases of cystic fibrosis were recorded. Recalled neonates (n = 398) included only 11 carriers. A receiver operating characteristic curve analysis showed that PAP above 8.0 ng/ml would select 0.76% of babies, including all those with cystic fibrosis, except for one with meconium ileus and two with mild CFTR mutations. Screening 27,146 babies with both PAP and IRT showed that only 0.12% had PAP > 8.0 ng/ml and IRT > 700 ng/ml, including all cases of cystic fibrosis. CONCLUSION: PAP is increased in most neonates with cystic fibrosis and could be used for CF screening. Its combination with IRT looks promising.

[Cushing's disease: role of feeding]. / Maladie de Cushing: Rôle de l'alimentation.

We report a clinical case of a patient with corticotropin dependent Cushing disease. In this patient ingestion of mixed meals is followed by an increase of ACTH and cortisol. This effects seems secondary to ingestion of proteins, and it can be reproduced by intravenous injection of aminoacids. The pattern observed is similar to what is observed in normal subjects. Neurotransmitter substrate from protein meals or after intravenous injection of aminoacids may influence the factors controlling ACTH secretion in the studied patient.

Neonatal screening for cystic fibrosis: result of a pilot study using both immunoreactive trypsinogen and cystic fibrosis gene mutation analyses.

We have evaluated a two-tier neonatal cystic fibrosis (CF) screening of immunoreactive trypsinogen (IRT) followed by CFTR gene mutation analysis using a systematic scanning of exons 7, 10, and 11, and, if necessary, by direct DNA sequencing. Over an 18-month period we screened 32,300 neonates born in the western part of Britanny. The first tier, involving IRT screening at 3 days of age, utilizes a low elevation of the trypsinogen level (600 ng/ml), which is highly sensitive. The second tier, which corresponds to the exhaustive screening for mutations in three exons of the gene, is highly specific for this population (Britanny). The false positive rate is very low, and no false negatives have been reported to date. This strategy has allowed the identification of five novel alleles (V322A, V317A, 1806 del A, R553G, G544S).

[Evolution of levels of free thyroxine and thyrotropin in treated Cushing disease]. / Evolution de la thyroxine libre et de la thyréostimuline au cours de la maladie de Cushing traitée.

OBJECTIVE: Determine the frequency and changes in thyroid hormones in Cushing's disease. METHODS: Free thyroxin and thyrotropin levels were measured in 11 patients (age range 17 to 60 years) with Cushing's disease both before and after resection of the pituitary adenoma. RESULTS: Free thyroxin levels were low (8.3 to 11.7 pmol/l) in 7 patients. These patients had no clinical manifestations of hypothyroidism. In 4 patients, cure of the pituitary adenoma led to normalization of the thyroid hormones 10 days after operation (13 to 55 pmol/l); in the other cases surgical cure was unsuccessful and thyroxin levels remained low. Cortisol levels were finally normalized in these patients after irradiation of the pituitary, a second pituitary operation, or bilateral resection of the adrenal glands in 2 patients. Normal thyroxin levels were thus achieved. There was no correlation between serum cortisol and free thyroxin. CONCLUSION: Thyroid hormones should be assayed regularly in patients with Cushing's disease as a supplementary control of treatment effectiveness.

Salt wastage, plasma volume contraction and hypokalemic paralysis in self-induced water intoxication.

Eleven episodes of severe hyponatremia secondary to hiccup-induced potomania were recorded in 3 years in a man who had essential hypertension, a low protein intake and a normal diluting ability. Paradoxical increase in hematocrit and plasma protein with acute extensive natriuresis was associated as well as urine potassium loss and hypokalemia producing paralysis in 1 episode. During a chronic water loading test, the defect in water excretion was related to a low urine solute delivery which was partially reverted by the natriuretic response to plasma volume expansion, promoting water diuresis. In acute water intoxication, this natriuretic response was exaggerated, producing a brisk water diuresis. Plasma volume was rapidly normalized but without any improvement in plasma sodium due to the concomitant negative sodium balance. Thus, water diuresis persisted until plasma volume was significantly contracted. Potassium loss appeared to be related to sodium excretion. Metabolic disturbances have not reoccurred despite persistent hiccup and potomania during 2 years of urea therapy.

Lack of effect of isradipine on cyclosporin pharmacokinetics.

The influence of isradipine as a long acting form (IcazR LP 5 mg) on cyclosporin pharmacokinetics was studied in six hypertensive renal transplant patients (mean age 37 yrs; mean body weight 62 kg). These patients received a mean daily cyclosporin dose of 307 mg in two equal intakes. Isradipine was orally administered once a day at a dose of 5 mg before the morning cyclosporin intake. Cyclosporin kinetics was assessed over a 0-12-h period, the day before (D-1) and 13 days (D+13) after isradipine treatment. Whole blood concentrations of cyclosporin were determined by radioimmunoassay (RIA) using the SandimmuneR-RIA kit (specific and non-specific monoclonal antibodies). Area under the blood concentration-time curve (AUC), the maximum blood concentration (Cmax) and the time to reach Cmax (Tmax) on D-1 and D+13 were not significantly different whatever the specificity of the RIA method. For example, the mean AUC +/- sd values were 5,247 +/- 2,255 (D-1) vs 5,317 +/- 1,675 (D+13) microgram.1(-1).h for the specific and 20,905 +/- 8,317 vs 19,327 +/- 5,758 microgram.1(-1).h for the non-specific determinations. Therefore, the pharmacokinetics of cyclosporin is not influenced by co-administration of isradipine at a therapeutic dosage. Moreover, the clinical results show that isradipine treatment was effective after 13 days administration (mean systolic blood pressure 132 vs 158 mm Hg, P < 0.05 and mean diastolic blood pressure 77 vs 93 mm Hg, P < 0.05 in supine position), and well tolerated throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Captopril induces correction of postrenal transplant erythremia.

Kidney transplant patients may develop post-transplant erythremia (PTE), and in order to avoid thromboembolism venesection, anticoagulation and native kidney removal have been suggested. We propose captopril as an alternative therapy for PTE. Seven hypertensive PTE patients, aged 42 +/- 10 years with stable renal function, were investigated to exclude primary or secondary polycythemia. All patients manifested true erythrocytosis [red blood cells (RBC) mass greater than 20% of predicted level] with concomitant increases in hematocrit and hemoglobin levels. Captopril was introduced in gradually increasing doses up to 75 mg/day under careful monitoring of blood pressure and renal function. Weekly follow-up was arranged to evaluate drug efficacy. After captopril, a significant reduction with normalization of the RBC mass (42 +/- 4 vs 31 +/- 5 ml/kg: P less than 0.005) was observed. The RBC counts and hematocrit and hemoglobin levels also decreased. One patient had recurrent erythrocytosis after captopril withdrawal. Captopril may be a simple, effective, and non aggressive treatment for postrenal transplant erythremia.

Circulating immune complexes containing bovine insulin in a patient with systemic allergic manifestations.

A woman treated for 15 days with bovine insulin for gestational diabetes presented with severe urticaria of the chest and back, distant from the injection site. She had neither local reaction nor general manifestations. Replacement of bovine NPH insulin by biosynthetic human NPH was followed by regression of urticaria. We isolated the circulating immune complex (CIC), mainly of IgG class, from the patient's serum. It disappeared when bovine insulin administration had been ceased for 48 h. There were no specific IgE-insulin-antibodies. The IgG-CIC were dissociated. Insulin was identified by RIA in the CIC. Insulin characterization was carried out by high-performance liquid chromatography (HPLC), which showed that the insulin in the complexes was injected bovine insulin.